PImage face;
//   PImage darkAreas; 
p p[]; 
ArrayList darkPoints;

void setup(){ 
  size(509,800,P2D); 
  smooth(); 

  face = loadImage("face.jpg");
  image(face, 0, 0,width,height);  // img, x, y, width, height 
  //    darkAreas = createImage(face.width, face.height, RGB);
  ArrayList darkPoints= new ArrayList();
  float threshold = 10; 
  loadPixels();
  //	darkAreas.loadPixels();

  for (int x=0; x < width; x++) {
    for (int y=0; y < height; y++){
	int loc = x + y*width;
	if (brightness(pixels[loc]) < threshold) { //???
	  //	darkAreas.pixels[loc] = color(0);
	  darkPoints.add(new Point(x,y));
	}
    }
  }
  Collections.shuffle(darkPoints);
  p=new p[100]; //number of particles
  for(int i=0; i<p.length; i++)p[i]=new p(i/1.0, ((Point)darkPoints.get(i)).x, ((Point)darkPoints.get(i)).y);  
} 

void draw(){   
  //frameRate(30); 
  //image(face, 0, 0);  // img, x, y, width, height

  stroke(255, 253, 235); 
  for(int i=0; i<p.length; i++) p[i].update();//render particles 
}

void mousePressed() {
  image(face, 0, 0);  // img, x, y, width, height 

}

class p { 
  float id,x,y,xp,yp,s,d; 

  public p(float _id, float _x, float _y) { 
    id=_id; 
    x=xp=_x; 
    y=yp=_y; 
    s=random(1,10); // SPEED (orig. 2,7)///////////////////////

  } 

  void update(){ 

    id+=0.01; 
    d=(noise(id,x/mouseY,y/mouseY)+0.5)*mouseY;  //original 0.5
    x+=cos(radians(d))*s; 
    y+=sin(radians(d))*s; 

    if(x<-10) x=xp=width+10;//offscreen rewind 
    if(x>width+100)x=xp=-10; 
    if(y<-10) y=yp=height+10; 
    if(y>height+10)y=yp=-10; 

    stroke(10);    
    line(xp,yp,x,y); 
    xp=x; 
    yp=y; 
  }
}